Only urban and sub-urban background monitoring stations have been included in the calculations. Data for Cyprus, Denmark, Finland, Luxembourg and Malta, are not included due to the geographical coverage of the Urban Audit.

Only urban and sub-urban background monitoring stations have been included in the calculations. Data for Cyprus, Denmark, Greece and Malta, are not included due to missing availability of operational urban and sub-urban background monitoring stations in the Urban Audit cities.

Only urban and sub-urban background monitoring stations have been included in the calculations. Data for Cyprus, Denmark, Finland and Malta, are not included due to missing availability of operational urban and sub-urban background monitoring stations in the Urban Audit cities.

Only urban and sub-urban background monitoring stations have been included in the calculations. Data for Bosnia and Herzegovina, Iceland, Liechtenstein, Luxembourg, Malta, the former Yugoslav Republic of Macedonia, Serbia, and Turkey are not included due to the geographical coverage of the Urban Audit and/or lack of air quality data.

Only urban and sub-urban background monitoring stations have been included in the calculations. Data for Cyprus is not included due to missing availability of operational urban and sub-urban background monitoring stations in the Urban Audit cities.

Only urban and sub-urban background monitoring stations have been included in the calculations. Data for Cyprus, Greece and Malta is not included due to missing availability of operational urban and sub-urban background monitoring stations in the Urban Audit cities.

Only urban and sub-urban background monitoring stations have been included in the calculations. Data for Cyprus, Luxembourg and Malta, are not included due to the geographical coverage of the Urban Audit.

Only urban and sub-urban background monitoring stations have been included in the calculations. Data for Bosnia and Herzegovina, Iceland, Liechtenstein, Luxembourg, Malta, the former Yugoslav Republic of Macedonia, Serbia, and Turkey are not included due to the geographical coverage of the Urban Audit and/or lack of air quality data.